ObjectiveTo detect the concentration of 8-isoprostane (8-iso-PG) in exhaled breath condensate (EBC) of patients with or at risk for ARDS in ventilation, and investigate its clinical significance.MethodsFifty-five patients with or at risk for ARDS in ventilation admitted between February 2014 and June 2016 were recruited as an experimental group, and simultaneous 30 normal cases were recruited as a control group. Their EBC was collected with EcoScreen condenser. The EBC 8-iso-PG level of the patients between different grades of ARDS (mild, moderate, and sever) or at risk for ARDS was compared, and the correlation of EBC 8-iso-PG with the clinical indicators was analyzed.ResultsThe 8-iso-PG levels in EBC and serum of the patients with or at risk for ARDS in ventilation were higher than those in the control group [EBC: (44.83±11.58) ng/L vs. (19.47±4.06) ng/L; serum: (481.53±444.94) ng/L vs. (19.91±17.60) ng/L] (all P<0.05). The EBC 8-iso-PG of the patients with moderate ARDS (n=15) and severe ARDS (n=7) [(47.18±11.68) ng/L and (50.29±11.06) ng/L] was higher than those with mild ARDS (n=7) or at risk for ARDS (n=26) [(33.04±7.62) ng/L) and (37.17±11.08) ng/L] (all P<0.05). However EBC 8-iso-PG was not different between the patients with mild ARDS and those at risk for ARDS (P>0.05 ). The increased EBC 8-iso-PG could predict ARDS with an area under the receiver operating curve of 0.73. The EBC 8-iso-PG of the patients with or at risk for ARDS was correlated with lung injury score (r=0.418, P<0.01), PaO2/FiO2 (r=–0.378, P<0.05), chest radiograph scores (r=0.410, P<0.05), AaDO2 (r=0.368, P<0.05), and APACHEⅡ score (r=0.718, P<0.05).ConclusionEBC 8-iso-PG can reflect the oxidative stress in lung of ARDS patients in ventilation, and can contribute to the diagnosis and evaluation for moderate and severe ARDS.
It is difficult to select the appropriate ventilation mode in clinical mechanical ventilation. This paper presents a nonlinear multi-compartment lung model to solve the difficulty. The purpose is to optimize respiratory airflow patterns and get the minimum of the work of inspiratory phrase and lung volume acceleration, minimum of the elastic potential energy and rapidity of airflow rate changes of expiratory phrase. Sigmoidal function is used to smooth the respiratory function of nonlinear equations. The equations are established to solve nonlinear boundary conditions BVP, and finally the problem was solved with gradient descent method. Experimental results showed that lung volume and the rate of airflow after optimization had good sensitivity and convergence speed. The results provide a theoretical basis for the development of multivariable controller monitoring critically ill mechanically ventilated patients.
Objective To study polyuria during mechanical ventilation in patients with chronic obstructive pulmonary disease ( COPD) and its possible mechanisms. Methods The plasma and urine concentrations of cystatin C ( CyC) were measured by enzyme immunometric assay in 26 COPD patients who received mechanical ventilation at timepoints of 0 h, 24 h, 48 h, 72 h and 1 week. And plasma levels of atrial natriuretic factor ( ANF ) , antidiuretic hormone ( ADH) and aldosterone ( ALD) were detected byradioimmunoassay at the same time-point. The urine volume was recorded every day. The samples of 30 healthy volunteers were measured as control. Results Polyuria phenomenon was found in majority of patients in 24 to 72 hours after mechanical ventilation. At 0h, the concentrations of plasma CyC, urine CyC,plasma ANF, ADH and ALD were all increased significantly compared with those of the control, respectively [ ( 4. 87 ±0. 51) mg/L vs ( 1. 29 ±0. 27) mg/L, ( 0. 58 ±0. 13) mg/L vs ( 0. 07 ±0. 02) mg/L, ( 37. 02 ±4. 35) pmol /L vs ( 22. 51 ±1. 18) pmol /L, ( 8. 61 ±1. 43) pmol /L vs ( 0.94 ±0. 34) pmol /L, ( 925. 4 ±142. 7) pmol /L vs ( 297. 5 ±135. 8) pmol /L, all P lt; 0. 01] , then decreased gradually after mechanical ventilation. The levels of plasma CyC and ANF at 24 h, plasma ADH at 72 h, and urine CyC at 1 week were similar to those of the control( all P gt;0. 05) , respectively, except the level of plasma ALD was still higher by 1 week( P lt; 0. 05) . Conclusions Polyuria is not a rare phenomenon for COPD patients receiving mechanical ventilation. Polyuria is related to the readjustment and mal-adaptation of ADH and reninangiotensin-aldosterone-systems during mechanical ventilation.
ObjectiveProlonged mechanical ventilation (PMV) is a prognostic marker for short-term adverse outcomes in patients after lung transplantation.The risk of prolonged mechanical ventilation after lung transplantation is still not clear. The study to identify the risk factors of prolonged mechanical ventilation (PMV) after lung transplantation.Methods This retrospective observational study recruited patients who underwent lung transplantation in Wuxi People’s Hospital from January 2020 to December 2022. Relevant information was collected from patients and donors, including recipient data (gender, age, BMI, blood type, comorbidities), donor data (age, BMI, time of endotracheal intubation, oxygenation index, history of smoking, and any comorbidity with multidrug-resistant bacterial infections), and surgical data (surgical mode, incision type, operation time, cold ischemia time of the donor lung, intraoperative bleeding, and ECMO support), and postoperative data (multi-resistant bacterial lung infection, multi-resistant bacterial bloodstream infection, and mean arterial pressure on postoperative admission to the monitoring unit). Patients with a duration of mechanical ventilation ≤72 hours were allocated to the non-prolonged mechanical ventilation group, and patients with a duration of mechanical ventilation>72 hours were allocated to the prolonged mechanical ventilation group. LASSO regression analysis was applied to screen risk factors., and a clinical prediction model for the risk of prolonged mechanical ventilation after lung.ResultsPatients who met the inclusion criteria were divided into the training set and the validation set. There were 307 cases in the training set group and 138 cases in the validation set group. The basic characteristics of the training set and the validation set were compared. There were statistically significant differences in the recipient’s BMI, donor’s gender, CRKP of the donor lung swab, whether the recipient had pulmonary infection before the operation, the type of transplantation, the cold ischemia time of the donor lung, whether ECMO was used during the operation, the duration of ECMO assistance, CRKP of sputum, and the CRE index of the recipient's anal test (P<0.05). 2. The results of the multivariate logistic regression model showed that female recipients, preoperative mechanical ventilation in recipients, preoperative pulmonary infection in recipients, intraoperative application of ECMO, and the detection of multi-drug resistant Acinetobacter baumannii, multi-drug resistant Klebsiella pneumoniae and maltoclomonas aeruginosa in postoperative sputum were independent risk factors for prolonged mechanical ventilation after lung transplantation. The AUC of the clinical prediction model in the training set and the validation set was 0.838 and 0.828 respectively, suggesting that the prediction model has good discrimination. In the decision curves of the training set and the validation set, the threshold probabilities of the curves in the range of 0.05-0.98 and 0.02-0.85 were higher than the two extreme lines, indicating that the model has certain clinical validity.ConclusionsFemale patients, Preoperative pulmonary infection, preoperative mechanical ventilation,blood type B, blood type O, application of ECMO assistance, multi-resistant Acinetobacter baumannii infection, multi-resistant Klebsiella pneumoniae infection, and multi-resistant Stenotrophomonas maltophilia infection are independent risk factors for PMV (prolonged mechanical ventilation) after lung transplantation.
ObjectiveTo investigate the condensate pollution in the pipeline of severe pneumonia patients undergoing mechanical ventilation.MethodsFrom January 2017 to January 2019, 120 patients with severe pneumonia treated by mechanical ventilation in our hospital were collected continuously. The lower respiratory tract secretions were collected for bacteriological examination. At the same time, the condensed water in the ventilator exhaust pipe was collected for bacteriological examination at 4, 8, 12, 16, 20 and 24 hours after tracheal intubation and mechanical ventilation. The bacterial contamination in the condensed water at different time points was analyzed and separated from the lower respiratory tract. The consistency of bacteria in secretion and drug resistance analysis of bacterial contamination in condensate water were carried out.ResultsOf the 120 patients with severe pneumonia after mechanical ventilation, isolates were cultured in the lower respiratory tract secretions of 102 patients. One strain was cultured in 88 cases, two strains were cultured in 10 cases, and three strains were cultured in 4 cases. The isolates were mainly Gram-negative bacteria (57.5%) and Gram-positive bacteria (42.5%). The most common isolates were Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter baumannii. The contamination rate of condensate water was 5.0% at 4 hours, 37.5% at 8 hours, 60.0% at 12 hours, 76.7% at 16 hours, 95.0% at 20 hours, and 100.0% at 24 hours, respectively. The bacterial contamination rate in condensate water at different time points was statistically significant (P=0.000). The pollution rate at 4 hours was significantly lower than that at 8 hours (P=0.000). Gram-negative bacteria accounted for 57.5% and Gram-positive bacteria accounted for 42.5%. The most common isolates were Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. The consistency of bacteria in lower respiratory tract and condensate water was 83.3% in severe pneumonia patients undergoing mechanical ventilation. The overall resistance of Pseudomonas aeruginosa, Acinetobacter baumannii and Staphylococcus aureus was higher, but the resistance to imipenem/cilastatin was lower.ConclusionsThe bacterial contamination in the condensate of patients with severe pneumonia during mechanical ventilation is serious. The pollution rate is low within 4 hours. It is consistent with the bacterial contamination in lower respiratory tract and the bacterial resistance is high.
ObjectiveTo investigate the predictive value of diaphragm rapid shallow breathing index (D-RBSI) in weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease (COPD).MethodsSeventy-six patients with COPD who were undergoing mechanical ventilation were enrolled in department of critical care medicine of our hospital from March 2016 to March 2017. The patient underwent spontaneous breathing test (SBT) using CPAP mode after weaning screening. When the SBT had started 10 min or the SBT failed, the patients' respiratory rate (RR) and tidal volume were recorded, and the diaphragmatic displacement (DD) of patients was measured by bedside ultrasound. The ratio of RR to DD (RR/DD) was calculated as D-RBSI, and the predictive value of D-RBSI on weaning results in mechanically ventilated patients with COPD was analyzed by receiver operating characteristic (ROC) curve.ResultsTwenty-eight patients failed weaning procedure. There were no significant differences in age and acute physiology and chronic health evaluation II scores between the successful group and the failed group. The DD of the patients in the successful group was greater than that of the failed group [(22±6) mm vs. (13±5) mm, P<0.001]. RBSI and D-RBSI of the successful group were lower than those of the failure group [RBSI: (40±14) breaths/(min·L)vs. (52±20) breaths/(min·L), P=0.003; D-RBSI: (0.95±0.51) breaths/(min·mm) vs. (1.79±0.83) breaths/(min·mm), P<0.001)]. There was a good correlation between the RBSI and D-RBSI in the two groups (R2=0.778, P<0.001). The area under the ROC curve predicted the weaning result by D-RBSI was higher than RBSI (0.85vs. 0.75, P<0 001="" the="" cutoff="" value="" of="" d-rbsi="">1.13 breaths/(min·mm) to predict weaning failure had a sensitivity of 0.82, and a specificity of 0.81.ConclusionThe rapid shallow breathing index of diaphragm can be effectively used to predict the weaning result of COPD patients during mechanical ventilation.